Their principle source of food is mice, but squirrels, snowshoe hares, and pikas are also popular.

The ermine's diet consists primarily of mice, but they also prey upon cottontails, small hares, porcupines, squirrels, pikas, and rats.

Elephant shrews (no relation), pikas, and Tupaia treeshrews share both absentee-like maternal care and diurnality - that is, they are active during the day, when prey is more easily spotted by predators.